Q. We assume that a "soft drape survey" is a survey which uses a pre-planned drape surface designed to minimize hard maneuvers and the accompanying unnecessary accelerations that may degrade the quality of the data. Can you confirm this? Is this drape surface to be supplied as part of the proposal?

A. This is correct. We will require a description of the drape surface design criteria in the proposal. The final drape surface may be accepted from the contractor after the RFP closes. The use of a drape surface is intended to keep the survey height off the ground close to the specified height while the survey area contains regions of different elevation.

Q. Given the relatively benign topography in the northern portion of the survey area, would Geoscience BC entertain splitting the survey area into two -- one of which is surveyed with a fixed wing aircraft and the other using a helicopter platform?

A. Yes, this would be considered, if this option is described fully in the proposal submitted to GBC.

Q. Does a proposal need to meet all the specifications outlined in the RFP to be considered?

A. The specifications requested in the GBC RFP are intended to be comparable to the airborne gravity surveys already completed for Geoscience BC in the QUEST and QUEST-West projects. If you would like to respond to the RFP with a proposal containing similar, but not identical technical specifications, your proposal will not be rejected on the basis of the failure to meet the specific specifications in the RFP. It will be considered on the basis of the specifications proposed, if these are in the overview comparable to the specifications of the surveys already completed in the Quest and Quest-West areas.

Q. Would you consider a longline gravity proposal as part of the QUEST-South Gravity RFP?

A. Our requirement is for a regional gravity survey comparable to the airborne surveys already completed in the Quest and Quest-west areas.

We have previously selected dynamic airborne gravity to provide high quality data, rapid data acquisition, and consistent coverage across the QUEST and QUEST-West project areas. The predictable and relatively low cost of dynamic airborne gravity surveying was also a significant factor in our choice of system.

If a long-line helicopter system can provide equivalent or better data and acquisition costs across the whole project area, then Geoscience BC would accept a long-line airborne gravity proposal for the Quest South gravity Request for Proposal (RFP). Please note that it should meet all of the RFP requirements, and that the data will be merged with the existing GBC data base to improve the gravity database for British Columbia.

In particular, the issue of the necessary station spacing, the ability to land a gravimeter in forested areas, terrain correction factors to be applied in rugged terrain, survey acquisition timing, and ongoing and timely QC of data during the survey progress should be addressed. Because a long-line survey is a substantially different method of data acquisition from the previous surveys, it would be carefully and rigorously scrutinized before a decision to accept it were made, even if substantial cost benefits were to accrue from such a decision.

It may be that an airborne long-line gravity survey is a very cost effective follow-on type of survey to add detail to areas, or features of interest in the regional airborne surveys. This is not a part of this QUEST South airborne gravity RFP, but may be addressed separately in Geoscience BC's regular requests for proposals for follow-up of the QUEST and QUEST-West project areas.

You can view the Previous Request for Proposals item: Tue Jul 21, 2009, CLOSED: Minerals Geoscience to Stimulate Exploration Activity in British Columbia